Any organisation putting AI into production ends up assessing it, whether for its own self-assessment, for conformity, or inside a regulatory sandbox. Assessment has two halves: technical tests that measure the system, and controls, compliance checklists whose questions map to specific EU AI Act provisions and return a readiness judgement rather than a metric. The AI Assessment Sandbox Configurator, developed open-source by LIST and the University of Luxembourg within the Luxembourg AI Factory, treats both as first-class catalogue entries behind one open plug-in API: qualify your AI system, select the tests and controls that fit it, and generate a sandbox à la carte that executes and reports on both, on your own infrastructure.